A decade ago, I used one of the hotel aggregator sites to reserve rooms for vacation, and as I call the hotel to double check something on my way to the airport, I find out that I don't actually have a reservation and my room is already occupied. They couldn't do anything about it, as it was the 3rd party aggregator's mistake.

Just getting the aggregator to admit, that no, even though their system says I have a reservation, the hotel confirmed it didn't exist took over an hour. I had to go through several layers of customer service, and I suspect different call centers, until someone called the hotel themselves and issued a refund.

It was miserable and stressful to do from the airport, I would have lost my mind if I had to deal with chatbots for what was already a terrible experience with an automated purchase.